3 files changed, 20 insertions, 9 deletions

diff --git a/fs/jffs2/nodelist.c b/fs/jffs2/nodelist.c
index ac2a4c422e32..4bf86088b3ae 100644
--- a/fs/jffs2/nodelist.c
+++ b/fs/jffs2/nodelist.c
@@ -52,7 +52,7 @@ void jffs2_add_fd_to_list(struct jffs2_sb_info *c, struct jffs2_full_dirent *new
         *prev = new;
 }
 
-void jffs2_truncate_fragtree(struct jffs2_sb_info *c, struct rb_root *list, uint32_t size)
+uint32_t jffs2_truncate_fragtree(struct jffs2_sb_info *c, struct rb_root *list, uint32_t size)
 {
         struct jffs2_node_frag *frag = jffs2_lookup_node_frag(list, size);
 
@@ -74,18 +74,24 @@ void jffs2_truncate_fragtree(struct jffs2_sb_info *c, struct rb_root *list, uint
         }
 
         if (size == 0)
-                return;
+                return 0;
 
-        /*
-         * If the last fragment starts at the RAM page boundary, it is
-         * REF_PRISTINE irrespective of its size.
-         */
         frag = frag_last(list);
+
+        /* Sanity check for truncation to longer than we started with... */
+        if (!frag)
+                return 0;
+        if (frag->ofs + frag->size < size)
+                return frag->ofs + frag->size;
+
+        /* If the last fragment starts at the RAM page boundary, it is
+         * REF_PRISTINE irrespective of its size. */
         if (frag->node && (frag->ofs & (PAGE_CACHE_SIZE - 1)) == 0) {
                 dbg_fragtree2("marking the last fragment 0x%08x-0x%08x REF_PRISTINE.\n",
                         frag->ofs, frag->ofs + frag->size);
                 frag->node->raw->flash_offset = ref_offset(frag->node->raw) | REF_PRISTINE;
         }
+        return size;
 }
 
 static void jffs2_obsolete_node_frag(struct jffs2_sb_info *c,
diff --git a/fs/jffs2/nodelist.h b/fs/jffs2/nodelist.h
index cb34cac5d0f8..25126a062cae 100644
--- a/fs/jffs2/nodelist.h
+++ b/fs/jffs2/nodelist.h
@@ -362,7 +362,7 @@ struct rb_node *rb_next(struct rb_node *);
 struct rb_node *rb_prev(struct rb_node *);
 void rb_replace_node(struct rb_node *victim, struct rb_node *new, struct rb_root *root);
 int jffs2_add_full_dnode_to_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f, struct jffs2_full_dnode *fn);
-void jffs2_truncate_fragtree (struct jffs2_sb_info *c, struct rb_root *list, uint32_t size);
+uint32_t jffs2_truncate_fragtree (struct jffs2_sb_info *c, struct rb_root *list, uint32_t size);
 struct jffs2_raw_node_ref *jffs2_link_node_ref(struct jffs2_sb_info *c,
                                                struct jffs2_eraseblock *jeb,
                                                uint32_t ofs, uint32_t len,
diff --git a/fs/jffs2/readinode.c b/fs/jffs2/readinode.c
index a42ffba2ed17..6aff38930b50 100644
--- a/fs/jffs2/readinode.c
+++ b/fs/jffs2/readinode.c
@@ -1132,7 +1132,7 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
                                         struct jffs2_raw_inode *latest_node)
 {
         struct jffs2_readinode_info rii;
-        uint32_t crc;
+        uint32_t crc, new_size;
         size_t retlen;
         int ret;
 
@@ -1233,7 +1233,12 @@ static int jffs2_do_read_inode_internal(struct jffs2_sb_info *c,
 
         case S_IFREG:
                 /* If it was a regular file, truncate it to the latest node's isize */
-                jffs2_truncate_fragtree(c, &f->fragtree, je32_to_cpu(latest_node->isize));
+                new_size = jffs2_truncate_fragtree(c, &f->fragtree, je32_to_cpu(latest_node->isize));
+                if (new_size != je32_to_cpu(latest_node->isize)) {
+                        JFFS2_WARNING("Truncating ino #%u to %d bytes failed because it only had %d bytes to start with!\n",
+                                      f->inocache->ino, je32_to_cpu(latest_node->isize), new_size);
+                        latest_node->isize = cpu_to_je32(new_size);
+                }
                 break;
 
         case S_IFLNK: